Don't let anyone tell you that their jealousy is happening because of something you've done. It's not. It's there because they're not confident in your feelings, and they're not confident about their own worth. That said, why not look around for someone who'll show you their admiration in a more flattering, outgoing way? Say, by taking you out to dinner, packing you picnic lunches and holding your hand across the table, for example? Sounds better, doesn't it?